Antihalation film



g- 1943 G. F. NADEAU ET AL 2,326,056

ANTIHALATION FILM Original Filed March 4, 1941 EMULSION. susa/we LA YER.

LLULOSE ESTER SUPPORT AN T/HALAT/ON LA YER 0F CELLULOSE ORGAN/CAC/DD/CARBOXYL/C ACID ESTER,-CARRYIN6 A DYE.

Fig.2

UE SENSITIVE EMULSION. EEN SENSITIVE EMULSION. RED SENSITIVE EMULSION.JUBB/NG LAYER.

LOSE A CE TA TE PROP/DNA TE SUPPORT AN T/HALAT/ON LA YER OF CELLULOSEACETATE PHTHALATE CONTAIN/N6 I4-28 ACE TVL AND 0-I6 PHTHAL YL, CARRY/N6A DYE Gale E/Vadeau A/fred Q S/ack IN VEN TORS BY Q EMA/M A TTORNE YSantihalation purposes.

Patented Aug. 3, 1943 AN TIHALATION FILM Gale F. Nadeau and Alfred D.Slack, Rochester, N. Y., assignors to Eastman Kodak Company, v IRochester, N. Y., a corporation of New Jersey Original application March4, 1941, Serial No.

881,695. Divided and this application November 1, 1941, Serial No.417,530

6 Claims.

This invention relates to a photographic film and more particularly to afilm provided with antihalation layers.

This application is a division of Nadeau and I Slack U. S. Patent2,311,073, granted February 16, 1943.

Coatings on the backs of films containing a dye or a superficial dyelayer removable in photographic processing solutions are well known forLess well known are antihalation layers which are designed to benonremovable. The disadvantages of the removable types of coatings arethe tendency of some coatings to deposit sludge in processing solutions,the tacky nature of some coatings, the known thermoplastic qualities ofother coatings which are in general undersirablaand furthermore, in thecase of certain resinous coatings their tendency to form insolubleproducts with the antihalation dye. been designed to avoid thesedifiiculties and to prevent the penetration of the dye into and theconsequent staining of the support. The success or ths practice dependsupon the selection of a material, for the dye carrier, which is, sufliciently permeable to processingsolutions, yet not soluble, that the dyegiving antihalation protection may be completely discharged whendesired.

The object of the present inventionis to provide a photographic filmwith a carrier for an Non-removable antihalation layers havea lightsensitive layer adhesively joined to the support by means of a subbinglayer.

Fig. 2 represents a multi-layer color film provided, on one side ofasubbed celluloseacetate propionate support, with emulsion layerssensitive to red, green and blue light, and on the opposite side, acellulose acetate phthalate antihalation layer containing a dye.

antihalation dye, said carrier being permeable to, but not soluble in,photographic processing solutions. Other objects appear hereinafter.

We have found that a cellulose organic acid dicarboxylic acid estercontaining substantially 4-8 acyl groups per C24 cellulose unit, ofwhich not more than one is a dicarboxylic acid acyl group and theremainder are aliphatic monobasic acid acyl groups of less than fivecarbon atoms, accomplishes our objectswhcn used as an antihalation layerin conjunction with a dye.

The general method we employ is to coat a photographic support with anemulsion, joining said emulsion to the support by means of suitablesubbing layers.

the other side of the support. We may vary this procedure by applyingthe antihalation layer between the light sensitive emulsicn layer andthe support. The antihalat. on layer. may also be coated before theemulsion layer.

Fig. 1 represents the general method of applying an antihalation layerand a dye to the back of a film support provided on the front side withWe then coat a water-permeable cellulose ester layer and a dye layeronto containing less than 4 acyl groups or more than one phthalyl groupD61.C24 cellulose unit are too soluble in photographic processingsolutions to be of use in the manner of our invention. Likewise, thoseesters containing more than 8 acyl groups are too impermeableto be usedin our invention. It is obvious that we contemplate, the use of othercellulose organic acid dicarboxylic acid esters, such as celluloseacetate propionate phthalate, cellulose acetate butyrate phthalate,cellulose acetate succinate, etc., the acyl content of which is of theorder described.

In designating the cellulose esters of our invention in terms of acylgroups, we use the expression substantially.

esters which are useful fall within the range approximated by thoseesters having 4-8 acyl groups C24 cellulose unit Thus, cellulose acetatephthalate containing more than about 14 per cent phthalyl, in additionto about 7 acyl groups per C24 unit is too permeable to photographicdeveloping solutions to be ofuse in our invention and this phthalylcontent corresponds to about 1 phthalyl group per C24 unit of cellulose.We use a C24 unit as the basic cellulose unit in order to avoidexpressing the dicarboxylic acid acyl content of an ester in fractionalterms in respect to the aliphaticmonobasic acid acyl content.

Several types of supports may be provided with the antihalation layer ofour invention. Cellulose esters such as cellulose acetate or cellulosenitrate, or mixed esters of cellulose, such as cellulose acetatepropionate and cellulose acetate butyrate, and opaque supports such aspa- This is due. to the fact that in analyzing our esters we find thatthose For in- .per, may all be so provided with .antihalation and methylCellosolve in suitable proportions.

We will now describe our invention with particular reference to theaccompanying drawing.

As shown in Fig. 1 of the accompanying drawing a cellulose ester supportis provided with .a subbing layer l2 which may be gelatin or othersuitable material, and over this is coated the emulsion layer l3 whichmay consist of a silver halide and colloid, such as gelatin, 2.cellulosic On'the opposite side of the support is coated theantihalation layer II or resinous material.

of our invention containing a dye in the outer stratum.

Fig. 2 shows a multilayer color film wherein a cellulose acetatepropionate support I0 is provided with the red, green and blue lightsensitive emulsion layers I 4, l5, and I6 respectively, adhesivelyjoined to the support by means of a subbing layer I2. On the oppositeside of the support is an antihalation layer H consisting of a celluloseacetate phthalate, 14-28% acetyl and 0-14% phthalyl, containing a dye inthe outer stratum. .a

The following example illustrates one method of producing a filmaccording to our invention, said example being intended to merelyillustrate our invention and is not to be taken as limiting the scope ofsaid invention.

Example A film base of cellulose acetate propionate containing 16%propionyl and 29% acetyl is coated with a 3% solution of celluloseacetate phthalate, acetyl content and phthalyl 13%, in a mixture of 45parts acetone and 55 parts of methanol. Over this layer is applied afugitive type of dye such as Acid Blue 2R or a dye of Color Index No.702N704, 705, or 707. The solvent mixture for the dye may vary over afairly wide range, although a mixture of 90 parts of meth-- anol and 10parts of water is generally satisfactory. On the other side of thesupport, now provided with an antihalation layer, is coated from solventsolution, a subbing layer consisting of a resin or a mixture of a resinand a cellulose ester followed by agelatin layer and a light'sensitiveemulsion. layer. Resins containing subbing layers have been more fullydescribed in a prior Patent U. S. 2,133,110, and others. A subbingsolution, containing gelatin and which is suitable for coating a gelatinlayer over a resin containing layer is also described therein. The filmmay be provided with differentially light-sensitive emulsion layerswhich may be sensitized in the natural order as shown in Fig. 2 ofthedrawing, or sensitized in the natural order and colored complementary tothe sensitivity as desired. A filter dye may be incorporated in one ofthe layers such as the blue sensitive layer in order to screen the lowerlayers from radiations which they are not intended to record. Also,there may be interposed between the emulsion layers a layer designed toreceive a sound record or this record may be printed in one of theemulsion layers. Itis obvious that we may reverse or vary the order ofdeposition of the layers on the support as in an alternative method wecoat the emulsion layers on the support before the antihalation and dyelayers.-

The photographic elements described are used in any of the well-knownprocesses designed to record an image in black-and-white or color. Afterexposure of the materials to an image the elements are usually developedt a negative and during this development or in a subsequent fixingtreatment the cellulose ester antihalation layer becomes sufiicientlyswollen to allow the penetration of the constituent removing theantihalation dye, but the cellulose ester of the anti halation layer isnot dissolved.

While we have described the use of permeable cellulose esters, inantihalation layers, and this is the preferred embodiment of ourinvention, it is evident that any process requiring a water permeable,but not soluble layer, with or without a dye, may be served by thematerials of our invention. Such processes are those of the photographictype which use sensitive films containing light filtering layers, thedye of which is to be removed at some stage in the processing treat-.ment.

The materials and examples of the present specification are illustrativeonly and it is to be understood that numerous methods and ingredientsmay be used Within the scope of the present description, and that thescope f our invention is to be taken as limited only by the scope of theappended claims.

What we claim is:

1. A photographic element free from halation which comprises a supportprovided with a light sensitive emulsion layer, and an antihalationlayer of a water-permeable cellulose ester containing substantially 4 to8 acyl groups per C24 cellulose unit, of which one is a dicarboxylicacid acyl group and the remainder are aliphatic monobasic acid acylgroups of less than live carbon atoms, said layer carrying alight-absorbing dye.

2. A photographic element free from halation which comprises a supportprovided with a light sensitive emulsion layer, and an antihalationlayer of, a water-permeable cellulose ester containing substantially 4to 8 acyl groups per C24 cellulose unit, of which one is a phthalylgroup and the remainder are aliphatic monobasic acyl groups of less thanfive carbon atoms, said layer carrying a light-absorbing dye.

3. A photographic element free from halation which comprises a supportprovided with a light sensitive emulsion layer, and an antihalationlayer of a water-permeable cellulose ester containing substantially 4 to8 acyl groups per 024 cellulose unit, of which one is a phthalyl groupand the remainder are acetyl groups, said layer carrying alight-absorbing dye.

4. A photographic element free from halation which comprises a supportprovided with a light sensitive emulsion layer, and an antihalationlayer of a Water-permeable cellulose ester containing, per C24 celluloseunit, substantially one phthalyl group and seven acetyl groups, saidlayer carrying a light-absorbing dye.

t 5. Aphotographic element free from halation which comprises acellulose acetate propionate support provided with a light sensitiveemulsion layer, and an antihalation layer of a water- 6. A photographicelement free from halation which comprises a support provided with alight sensitive emulsion layer, and an antihalation layer of awater-permeable cellulose aliphatic monobasic organic acid-dicarboxylicacid, ester containing substantially 4 to 8 aliphatic monobasic organicacid acyl and dicarboxylic acid acyl groups per C24 cellulose unit, ofwhich not more than one is a dicarboxylic acid acyl group and theremainder are aliphatic monobasic acid acyl groups of less than fivecarbon atoms, said layer carrying a light-absorbing dye.

GALE F. NADEAU.- ALFRED D. SLACK.

